Volume before the spike on Cryptsy was often around 40btc a day. Right now it's about 110 but I'm not sure how much of that related to Evan's post about RC3 and open source.
I understand what you're saying about the drop off though and you may be right about it being close to dropping off in value, but I also think that there a few scattered posts of people who come across Darkcoin and genuinely believe in it (not just proclaiming that it is going to the moon). I think they (like me) experienced the "satori" moment when they realised the genuine gap in the market that this coin can fill.